The early trials of coronary artery surgery compared to conservative management in patients with non-acute coronary heart disease are no longer relevant because of recent advances in surgery and medical treatment. There have been no recent major trials, including trials of female patients. Only one recent limited trial has been reported about patients over 70 years. The widespread adoption of angioplasty has taken place without adequate trial evidence to suggest that angioplasty is superior to medical treatment in many patients subjected to this invasive procedure. The limited evidence would suggest that medical treatment is less effective in the relief of chronic angina but more effective in terms of further events. Current uncertainties and important advances in angioplasty and medical treatment are compelling reasons for proper trials. Medical treatment has rarely been defined in the earlier surgical and angioplasty trials. Anti-platelet agents and statins were not available and risk factor identification and modification were never referred to. Medical treatment to-day includes risk factor identification and modification, graduated aerobic exercises, the use of anti-platelet agents and statins, B-blockers and ACE inhibitors where indicated, and symptomatic treatment, including the nitrates for chronic angina. The paucity of recent trials comparing invasive procedures with medical treatment leaves uncertainties about the management of many patients with coronary heart disease and these uncertainties are increased by poor adherence to the limited trial evidence available. It raises doubts about our adherence to evidence based cardiology and concerns about the wide variations in the management of patients in different centres. It has important implications relating to the cost of overstretched health delivery systems and therefore has political implications. Current uncertainties can only be resolved by new trials to assess the indications for the different treatment modalities and by more effective audit to ensure that accepted indications are adhered to.